power quality | Leonardo ENERGY

Ferroresonance Effects

Fri, 05/09/2008 - 14:57

Power Injection Control System and Experimental Model based on Manufacturer Characteristic Curves for a Photovoltaic Generation

Tue, 05/06/2008 - 14:44

This paper attempts to validate the performance of a power injection control block for Photovoltaic Generation Systems (PVGS). This device uses a control module based on detecting the power injected into the supply by the inverter, instead of measuring the power generated by the PVGS. The performance is evaluated using the concept of Maximum Energy Curve that takes into account both transient and permanent control performance.

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Stochastic Estimation of Voltage Sag Due to Faults in the Power System by Using PSCAD/EMTDC Software as a Tool for Simulation

Hans De Keulenaer

Tue, 05/06/2008 - 14:38

Faults in the power system are major cause of voltage sag. Voltage sag in the power system due to fault can be symmetrical or unsymmetrical. For sensitive loads it is necessary to estimate how many times in year the voltage at their terminal will experience sag to avoid tripping of operation. Several stochastic methods for estimation of number of sags are developed in recent years. In different methods of sag prediction there is need to do lengthy programming or calculations.

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Passive Filter Design for Three-Phase Inverter Interfacing in Distributed Generation

Hans De Keulenaer

Tue, 05/06/2008 - 14:36

With the growing use of inverters in distributed generation, the problem of injected harmonics becomes critical. These harmonics require the connection of low pass filters between the inverter and the network. This paper presents a design method for the output LC filter in grid coupled applications in distributed generation systems. The design is according to the harmonics standards that determine the level of current harmonics injected into the grid network.

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The Use of the SSC as Reactive Power Compensator

Hans De Keulenaer

Tue, 05/06/2008 - 14:34

The paper deals with the possibility of employing the Custom Power Static Series Compensator (SSC), whose primary aim is to compensate voltage sags, also as a Reactive Power Compensator. The idea arises from the observation that such device does not work for the majority of time and can therefore be usefully employed for other purposes, such as power factor corrections. To this aim, an “ad hoc” control algorithm is developed and thoroughly discussed in the paper.

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Three-level Modulation Techniques to Reduce Instantaneous Common Mode Voltage in Induction Machines

Hans De Keulenaer

Tue, 05/06/2008 - 14:33

Problems on inverter motor drives such as bearing currents are introduced due to common mode voltages. Different solutions are proposed on literature, for two-level or multilevel inverter. Instantaneous zero common mode voltage by using a three-level inverted could be achieved. This paper proposes a commutation strategy that allows zero common mode voltage by using medium vectors, and also a new representation as a plane on the commutation space is defined which is called zero common mode voltage plane.

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Influences of a “Hybrid Grid” on the Network’s Voltage Quality and Supply Reliability

Hans De Keulenaer

Tue, 05/06/2008 - 14:30

The electricity is a basic need for functioning of modern society. In the deregulated electricity market, delivering quality power to the clients is a challenge for the utilities. In this paper, a “hybrid grid” is discussed that consists of centralized generations and localized distributed generations which may be comprised of small-scale conventional and sustainable sources. Energy storage option is also integrated in the hybrid-grid. Simulations are done on a test network, using “Power-Factory” software.

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Wind Turbine Harmonics Caused by Unbalanced Grid Currents

Hans De Keulenaer

Tue, 05/06/2008 - 14:27

Klaus-Dieter Dettmann, Steffen Schostan, Detlef Schulz

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Electromagnetic Coupling of the Electrical Drive – EMC (Part I)

Hans De Keulenaer

Tue, 05/06/2008 - 14:24

The paper deals with the general analysis of one part of the electromagnetic compatibility (EMC) problem - the electromagnetic coupling applied in the field of power electrical systems. Theoretical analysis of above mentioned problem, based on the impact investigation of the electromagnetic wave propagation, is described in part I. Obtained results can be used for predictive stating of EMC quality of individual new electrotechnical products.

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Quasi-Instantaneous Generation of Reference Signals for Hybrid Compensator Control

Hans De Keulenaer

Tue, 05/06/2008 - 14:20

Power variation of a customer load can disturb other loads in distribution systems and compensators for such loads are sometimes needed. Voltages and currents in systems with such loads can be asymmetrical, nonperiodic, distorted and even unpredictable. consequently, reference signals for the compensator control have to be generated in a situation where the power properties of the load are not well specified.

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Ancillary consumption of railways

Stefan Fassbinder

Fri, 05/02/2008 - 11:47

When you are lucky enough to have the insight into the interior technical details of a German ICE 2 high-speed railcar, you may realize that the main transformer has 7 output windings. Next to 4 windings with a 1 MVA output for the 4 inverter drives, you will find 3 windings for ancillary supplies, among them one for the carriage heating with an output rating of 500 kW!

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Energy storage systems—Characteristics and comparisons

Hans De Keulenaer

Wed, 04/30/2008 - 19:18

Decentralised production means greater stability problems for the electricity system. This paper investigates a wide range of storage solutions. Rather than just looking at storage capacity or economics, it considers the very different technical characteristics of storage options in terms of available power, efficiency, durability and reliability.

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Future Power Systems

By:

Stephen Browning

/ Published on:

Mon, 04/28/2008 - 15:32

Introduction to the 'Big+Little' picture

The way in which electricity is to be supplied is subject to radical change. Distributed and Renewable Generation, together with Demand Management, is being promoted to reduce the use of central fossil fired plant, increase efficiency in delivery of energy and reduce emissions.

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European Power Quality Survey Results

By:

Hans De Keulenaer

/ Published on:

Tue, 04/22/2008 - 14:51

This mini site presents the results of European Power Quality Survey with a focus on power quality critical sectors.

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Designing Industrial Processes for PQ Resiliency

Isabelle Heriakian

Fri, 04/18/2008 - 19:23

Brian Fortenbery from EPRI presents the Industrial Design Guide (IDG). The IDG provides a strong technical basis for working with industrial end users in power quality, distribution, and economic development activities. The tool describes in detail such industrial processes as injection-molded plastics and CNC machining, includes electrical diagrams of the processes and sub-processes, and discusses the economics of process-associated downtime. The descriptions and drawings are interactive, leading the user to important power quality considerations, such as sensitive components, test protocols, solutions, and applications. This authoritative guide to industrial processes can be used to train new power quality engineers, refresh seasoned representatives, and enhance the credibility of all employees in the presence of end users, and the web-based format makes it easy for even novices to use.

This interview is in 2 parts.

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Profitable investment opportunities

By:

Isabelle Heriakian

/ Published on:

Tue, 04/15/2008 - 17:52

The chemical sector suffers unnecessary financial losses caused by their own electrical power systems that often cannot cope with a variable electric power supply. ECI’s Survey has identified many losses and much wastage due to poor PQ throughout the industry’s different production centres. It has demonstrated that PQ solutions often cost less than the financial losses they resolve.

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Understanding the problems – designing the solutions

By:

Isabelle Heriakian

/ Published on:

Tue, 04/15/2008 - 17:48

ECI’s PQ Survey demonstrates that the majority of the PQ problems faced by the chemical industry result from the end users’ own electrical installations’ inadequate design. The solutions therefore lie very much in the industry’s own hands.

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